WO2023118405A1 - Cooling device - Google Patents

Abstract

The invention relates to a cooling device (1) for cooling components (101), comprising a base region (2) which can be heat-conductingly connected to a component (101) to be cooled, a deflecting region (3), an intermediate region (4) between the base region (2) and the deflecting region (3), and a cooling channel (5), which has a meandering shape and has a number of central segments (51) and a number of deflecting segments (52), wherein each of the central segments (51) extends from the base region (2) to the deflecting region (3), and each of the deflecting segments (52) produces a direction reversal within the base region (2) and within the deflecting region (3) and connects two respective central segments (51) together. The cooling channel (5) is filled with a working medium (6) which is simultaneously gaseous and liquid in the cooling channel (5). According to the invention, an inner wall (53) of the cooling channel (5) has at least one locally delimited surface structure (54) which contacts the working medium (6).

Description

Description

title

cooler

State of the art

The present invention relates to a cooling device for cooling components and an electronic arrangement.

Power semiconductors in power electronics usually carry high currents, which can lead to high heat losses. Such power semiconductors often need to be cooled, for example to prevent damage from overheating.

For example, liquid cooling or air cooling can be used for cooling. Furthermore, so-called pulsating heat pipe structures can be used as cooling devices for cooling. These are particularly suitable for direct integration into existing components with the aim of efficiently dissipating heat from thermal hotspots to heat sinks. In this case, the heat is usually first spread from the place where the heat is introduced by means of heat conduction. A cooling device designed as a pulsating heat pipe includes a cooling channel in the cooling device, which is designed in a meandering shape and is filled with a working medium that is present in the cooling channel in gaseous and liquid form at the same time. In the cooling device, heat is transferred to the cooling channel in a base region, so that the working medium in the cooling channel locally evaporates. This creates pressure gradients that transport the working medium through the cooling channel. The vapor bubbles also migrate into a condenser part of the cooling channel and condense there. The heat is thereby transmitted through the walls of the

Capacitor and, for example, also released to the environment via ribbing. Overall, therefore, the heat that is introduced into the cooling device in the base area is distributed over the entire cooling device. A cooling device designed as a pulsating heat pipe thus serves as a heat-spreading design element.

Disclosure of Invention

According to the invention, a cooling device for cooling components is proposed. The cooling device comprises a base area, which can be thermally conductively connected to a component to be cooled, a deflection area, an intermediate area between the base area and the deflection area, and a cooling channel, which is designed in a meandering manner and has a number of middle segments and a number of deflection segments, with the middle segments each extending from extend from the base area to the deflection area, with the deflection segments each forming a reversal of direction within the base area and within the deflection area and connecting two central segments to each other, with the cooling channel being filled with a working medium which is present in the cooling channel in gaseous and liquid form at the same time. According to the invention, an inner wall of the cooling channel has at least one specifically locally limited surface structure with increased roughness, which is in contact with the working medium. According to the prior art, the cooling channels have an identical surface across all of their section areas. Structurally, in particular with regard to measurable roughness values, this is characterized by the manufacturing process used to form the cooling channels. The cooling channels are formed, for example, by milling, extrusion or deep drawing. Without special precautions, the wall surfaces forming the cooling channel have a square roughness Rq (see EN ISO 4287) in the range of 0.2 pm - 0.5 pm. The rougher the surface is due to the manufacturing process, the greater the flow resistance for the working medium within the cooling channel. In this respect, the aim is normally to use the manufacturing process used to make the cooling channels cost-effective, but also to have a smooth, continuous path surface, ie with low roughness values, and thus also to keep the flow resistance small.

Advantages of the Invention

Compared to the prior art, the cooling device with the features of the independent claim has a greatly increased cooling effect. When heat is supplied to the base area, that is to say when the component adjoining it heats up, the heat is transferred from the base area to the cooling channel with the working medium located therein. As a result, a phase change and a flow of the working medium can be generated within the cooling channel, as a result of which the heat is transported from the base area in the direction of the intermediate area. On an outside of the cooling device, in particular in the intermediate area and the deflection area, the heat is given off to the ambient air by convection. As a result, an in particular irregular, pulsating or oscillating phase transition of the working medium can be generated. A pulsating or oscillating flow of the working medium in the cooling channel can also be present. The cooling device thus works according to the principle of a pulsating heat pipe, also known as a pulsating heat pipe.

Due to the specifically locally delimited surface structure with increased roughness on the inner wall of the cooling channel, this is provided with different roughness values over its entire extension area over then defined extension sections. For example, the cooling channel can be designed in a known manner and continuously have a wall surface with a square roughness in the range of 0.2 μm-0.5 μm. Subsequently, the wall surface is specifically roughened locally at defined extension sections of the cooling channel, limited to these sections, so that the squared roughness is increased here to a value range of 0.8 μm-7 μm. At this point of the specifically locally limited surface structure with increased squared roughness Rq, the evaporation of the working medium is advantageously influenced. Micro vapor bubbles initially form on the said surface structure in the working medium, which detach from a certain point or from the surface structure in grow the cooling channel. A rough, for example porous or heavily structured, surface structure promotes evaporation, since the structure provides an increased surface area for evaporation in the area of the surface structure and thus lower surface tensions have to be overcome when bubbles form. This leads to a smaller required temperature difference between the inner wall of the cooling channel and the working medium. As a result, the evaporation is initialized very early on between the inner wall of the cooling channel and the working medium and thus an advantageously improved heat transfer between the cooling channel and the working medium is brought about. The locally limited surface structure with increased square roughness therefore serves in the function of advantageous germ cells for the early formation of evaporation bubbles. Even if the other cooling channel sections continue to have surfaces that are as smooth as possible with low roughness values according to the prior art, the cooling capacity of the cooling device is increased on average through the targeted, locally limited increase in the roughness values within defined cooling channel sections.

In a pulsating heat pipe, the evaporation process of the working medium in the cooling channel can thus be optimized by the targeted, locally limited surface structure with increased square roughness on the inner wall of the cooling channel. For subsequent, locally limited roughening of the wall surface within defined cooling channel sections, the glass bead method, which is otherwise known for other purposes, can be used, for example. When glass beads of a defined size and at a defined speed hit the surface wall, the smallest mechanical indentations and indentations are created, which increase the surface roughness. Alternatively, sandblasting can also be used. Due to the rather undefined shape of the sand grains, the roughness can be significantly increased. Both the shape and the size and speed of the particles that hit the wall surface ultimately influence the roughness values that can be formed. It has been shown to be advantageous that a square roughness in the range of 2 μm-5 μm represents a good relationship with regard to the optimized performance of the cooling device and the costs incurred for producing increased roughness values. In principle, other methods are also conceivable which can be used for a locally limited surface roughening, for example a laser method, an etching method, a mechanical roughening, for example by means of brushes. Also, for example during milling or other methods, the roughness of the wall surface defined in sections can be adapted in a correspondingly varying manner during the production of the cooling channel in one process step, for example by changing manufacturing parameters in the defined cooling channel section.

The functioning of the pulsating heat pipe, the pulsating heat pipe, can be specifically influenced and controlled by a targeted selection of the points in the cooling channel at which such locally limited surface structures are provided. The combination of the geometry of the cooling channel and the selection of the points with said locally limited surface structures in the cooling channel can influence the behavior of the working medium in the cooling channel, change the flow regime in the cooling device in a targeted manner and thus improve heat transport in the cooling device. Advantageously, the specifically locally limited surface structure with increased square roughness in a cooling channel cross section does not have to be formed continuously over the closed circumferential channel wall. The specifically locally delimited surface structure with an increased square roughness is therefore preferably only formed on a partial area of the closed circumferential channel wall within a cooling channel cross section. More preferably, this partial area is arranged within the half of the closed circumferential duct wall that faces the heat dissipation side of the cooling device. The partial area is therefore preferably arranged on the evaporator side of the cooling device and in particular comprises up to half the area of the closed circumferential channel wall within a cooling channel cross section. The advantage here is based in particular on the effective temperature difference between the evaporator side and the condensation side of the cooling device, with increased roughness on the evaporator side being sufficient for early bubble formation. In addition, the flow resistance on the condensation side remains low, so that overall there is a very good balance between the flow resistance that is effectively set and the increased cooling performance that can be achieved.

Further advantageous refinements and developments of the invention are made possible by the features specified in the dependent claims. According to an advantageous exemplary embodiment, it is provided that the named locally limited surface structure of the inner wall of the cooling channel is formed in at least one deflection segment in the base area of the cooling device. The base area serves to absorb heat from the component and as an evaporator for the working medium that is arranged in the cooling channel. A specifically locally limited surface structure with increased quadratic roughness formed in the base area of the cooling device, which acts as an evaporator part, leads to improved evaporation on this surface structure and thus to improved evaporation in the base area. Due to the fact that the local surface structure is formed locally in the base area, the flow resistance in the cooling channel is only negatively influenced at these points and thus only insignificantly overall, while the evaporation of the working medium is clearly promoted. The evaporation-side heat transfer between the cooling channel and the working medium, which can be the bottleneck for the thermal performance of the cooling device, especially when cooling components with high heat flux density, is thus improved by the targeted, locally limited surface structure with increased square roughness and the dissipation of the heat from the component improved by the cooling device. Since the heat from the component is absorbed by the base area and the deflection segments arranged in the base area and is given off to the working liquid in the cooling channel, the said surface structure formed in the deflection segments can improve evaporation, so that the heat from the component is transferred directly into the deflection segments causes the working liquid to evaporate.

According to an advantageous exemplary embodiment, it is provided that the locally limited surface structure with increased quadratic roughness is formed on one side in the deflection segment in the base area. This means that of two cooling channel sections adjoining the deflection segment, the locally limited surface structure is formed with an increased square roughness only on the side of one of these cooling channel sections. Advantageously, pressure gradients can arise in one direction in the same direction, which ensure that the flow of the working fluid takes place in a preferred direction. Instead of oscillating movements of the work equipment with frequent changes of direction, as can normally occur in heat sinks designed as pulsating heat pipes, the working fluid preferably flows circumferentially through the cooling channel. In this way, the global flow regime can advantageously be converted from an exclusively pulsating to a circulating-pulsating flow of the working medium. A circulating-pulsating flow generated in this way is a pulsating movement superimposed by a circulation, which has a greatly increased thermal performance. For this purpose, the fact is used that the bubbles forming in the cooling channel, after their formation on the locally limited surface structure, preferably migrate into the straight central segments of the cooling channel instead of passing through the deflection section in the base area. If in the base area in the deflection sections only one side of the deflection section is provided with a targeted, locally limited surface structure with increased squared roughness, while the other side of the same deflection section does not have such a targeted, locally limited surface structure with increased squared roughness, but is smooth, always arise the side with the specifically localized surface structure prefers bubbles. Since these bubbles then always continue to flow on the side where they originated into the straight central segment of the cooling channel, there is a preferred direction of flow at each deflection section in the base area. Viewed over the entire cooling device, this creates a superimposed circulating movement that significantly improves the heat transfer.

According to an advantageous exemplary embodiment, it is provided that the deflection segments are formed in a row next to one another in the base area, with the targeted, locally limited surface structure having an increased square roughness being formed in at least one deflection segment on the outside of the row, with at least one on the inside of the row Deflection segment has no such locally limited surface structure. Depending on the geometry, orientation to gravity and the power range of the cooling device with the pulsating heat pipe, not all areas of the cooling channel are always in the same flow regime or not all channels are active. For example, in the case of narrow channel bends at the deflection segments, a vertical orientation to gravity and heating from below, and a low power range, especially when the cooling channel is filled with working fluid, the outer areas of the cooling channel can be deactivated. On the one hand, this can be due to the fact that when the heating is uniform, the temperature in the inner areas of the cooling channel is greatest in the base area and towards the sides falls off. On the other hand, the globally low heat flow leads to a low bubble formation rate, which is crucial for the kinetics of the fluid. In addition, the high pressure gradients in the narrow deflection segments ensure that bubbles preferentially migrate into the straight central segments of the cooling channel after they have formed, instead of first migrating through the deflection segment and then into the adjacent central segment. So it can happen that although the middle areas of the cooling channel pulsate, the outer areas hardly pulsate or not as desired. This effect is counteracted in an advantageous manner by specifically providing locally limited surface structures with increased square roughness in the base area in the outer deflection segments. Such surface structures increase the bubble formation rate in the outer deflection segments and the outer areas of the cooling channel are kinetically activated. This leads to a globally improved heat transfer in the cooling device. The cooling device in the form of a pulsating heat pipe is preferably at least thermally connected on its evaporation side to an electrical and/or electronic component to be cooled, preferably a power semiconductor or a chip. The outer deflection segments, which are not covered by the heat dissipation surface of the electrical and/or electronic component in a vertical plan view of the evaporator side, have the specifically locally limited surface structure with increased square roughness. In this way, the components of the working medium that are otherwise on average liquid can be compensated for by easier bubble formation. In contrast, none of the other cooling channel sections that are covered by the heat dissipation surface of the electrical and/or electronic component and are therefore located in the hotspot area have any such surface structures. In general, it is conceivable to form the specifically locally limited surface structures with increasingly high roughness values the further away they are from a hot spot.

According to an advantageous exemplary embodiment, it is provided that a targeted, locally limited surface structure with increased quadratic roughness is formed in each of the two outer deflection segments in the base area, with the deflection segments lying on the inside in the row not having such a locally limited surface structure. According to an advantageous exemplary embodiment, it is provided that at least one specifically locally limited surface structure with an increased square roughness is formed in at least one central segment. In this way, the starting behavior and the thermal resistance of the cooling device can also be optimized in non-preferred orientations of the cooling device. A non-preferred direction is understood to mean an orientation of the cooling device in space in which the base area of the cooling device, from which the heat of the component to be cooled is absorbed, is not located at the bottom. The base area of the cooling device is not oriented downwards in space, but upwards or to the side. If the base area of the cooling device is oriented upwards in the room and the cooling device is thus heated from above, there is no heat flow in the cooling device; the heat flow is at a standstill, in the so-called dryout. This means that there is only vapor in the base area and the entire liquid collects in the deflection area or in the intermediate area. The same effect can occur with horizontal orientation even at very low power. This can lead to the failure of the cooling device to function as a pulsating heat pipe. Targeted, locally limited surface structures with increased square roughness in the middle segments can counteract the standstill of the heat flow. In the dryout, the liquid phase already collects at these points if the filling level is sufficient. If heat is now introduced into the base area, this is transported via thermal conduction via the intermediate area in the direction of the deflection area. If the heat flow reaches the said locally limited surface structure, this quickly leads to the formation of bubbles and to the cooling device starting to function as a pulsating heat pipe. In the process, the liquid phase is again transported into the base area, so that good heat transfer can be achieved again. If the pulsating heat pipe has not yet started, the specifically locally limited surface structure with increased square roughness is arranged in the area of the upper edge of the liquid level of the working medium.

According to an advantageous exemplary embodiment, it is provided that at least one such locally limited surface structure is formed in all middle segments.

According to an advantageous exemplary embodiment, it is provided that the inner wall of the cooling channel has a locally increased surface structure in the area of the targeted local surface structure has roughness. A local surface structure with increased roughness advantageously promotes local evaporation of the working medium in the cooling channel. On the local surface structure, the cooling channel has a roughness that is increased compared to the region of the cooling channel surrounding the local surface structure.

According to an advantageous exemplary embodiment, it is provided that the inner wall of the cooling channel in the area of the specifically locally limited surface structure has a higher roughness than the inner wall of the cooling channel on the deflection segments in the deflection area. In this way, the evaporation of the working medium can be increased on the specifically locally limited surface structure and at the same time a low flow resistance can be achieved on the deflection segments in the deflection area, which enables an undisturbed flow of the working medium through the cooling channel in the deflection area.

Furthermore, the invention leads to an electronics arrangement which includes the described cooling device. Furthermore, the electronics arrangement includes a component to be cooled, which is in particular a semiconductor component, for example of a motor vehicle. The component to be cooled is thermally conductively connected to a base area of the cooling device. The cooling device enables particularly effective and reliable cooling of the component in order to avoid overheating.

Brief description of the drawings

An embodiment of the invention is shown in the drawing and is explained in more detail in the following description. It shows

1 shows a schematic representation of a first exemplary embodiment of the cooling device,

2 shows a schematic representation of a second exemplary embodiment of the cooling device,

3 shows a schematic representation of a third exemplary embodiment of the cooling device. Embodiments of the invention

The figures show schematic representations of exemplary embodiments of an electronics arrangement 100 with a cooling device 1. The cooling device 1 can be used to cool electronics or other hotspots of all kinds, for example to cool power electronics in electric vehicles, passive battery cooling, cooling of engine control devices, charging stations or drive Units are used in eBikes. The cooling devices 1 of the three different exemplary embodiments in the three different figures differ in terms of the locations in the cooling channel 5 where locally limited surface structures 54 with an increased square roughness are provided in a targeted manner.

The electronics arrangement 100 includes a component 101 , for example with power electronics, for example a semiconductor component, and a cooling device 1 . The cooling device 1 is designed to cool the component 101 . For this purpose, a base area 2 of the cooling device 1 is connected to the component 101 in a thermally conductive manner. For this purpose, the component 101 lies, for example, directly or indirectly on the base area 2 of the cooling device.

The cooling device 1 comprises a cooling channel 5 which has a number of central segments 51 and a number of deflection segments 52 . The cooling channel 5 runs in the cooling device 1. The cooling channel 5 has a meandering design. In particular, a shape is considered to be meandering if it has a plurality of changes in direction, preferably in one plane. For example, meandering can also be referred to as serpentine. The cooling channel 5 can be designed as a meandering curved tube. The cooling channel 5 can have, for example, a circular, an elliptical or a rectangular cross section. The cooling channel 5 can have a diameter of approximately 0.5 to 2 mm, for example.

The cooling channel 5 can be formed, for example, in a one-piece curved tube. However, the cooling channel 5 can also be formed in a multi-part cooling device 1, which can be composed, for example, of several tube segments and/or plates or other components can. The cooling channel 5 can, for example, run at least partially in one or more solid plates, for example in the deflection area 3 and/or in the intermediate area 4 and/or in the base area 2 . For example, cutouts can be provided in the solid plates, which form the cooling channel 5 or parts of the cooling channel 5 . The cooling channel 5 can, for example, also run between sheets that are stacked to form a cooling device 1 and welded or soldered to one another.

The cooling channel 5 is preferably tubular. The cooling channel 5 is preferably of closed design. For this purpose, the cooling channel 5 preferably has a connecting area 58 which is preferably located within the deflection area 3 and which forms a closed circuit of the cooling channel 5 . More preferably, the cooling channel 5 has a valve in order, for example, to allow the cooling channel 5 to be evacuated and the cooling channel 5 to be filled with the working medium 6 .

As shown in the figures, the cooling channel 5 extends from the base area 2 through an intermediate area 4 to a deflection area 3. The middle segments 51 each extend from the base area 2 to the deflection area 3, i.e. through the intermediate area 4. All center segments 51 are straight and arranged parallel to one another. The deflection segments 52 are each arranged at the ends of the middle segments 51 in the deflection area 3 and in the base area 2 and each form a direction reversal. A deflection segment 52 connects two central segments 51 to one another.

The deflection segments 52 are each U-shaped, for example, and have a bending radius. As a result, the middle segments 51 are arranged at a distance from one another which corresponds to twice the bending radius 55 . On the base area side, the deflection segments 52 run, for example, in a base plate that can form a planar contact with the component 101 . The base plate has a high thermal conductivity, for example, and is made of aluminum, for example, in order to enable good heat conduction and thermal connection of the component 101 and effective heat dissipation from the component 101 . Further the cooling device 1 is preferably made entirely of aluminum in order to be inexpensive and thermally well conductive.

Within the cooling channel 5 there is a working medium 6 which is simultaneously in the liquid and in the gaseous state. The working medium 6 is present in the cooling channel 5 in gaseous and liquid form at the same time, in other words partly gaseous and partly liquid. This means that the working medium 6 is present in two phases in the cooling channel 5 . In particular, gas bubbles and liquid columns are simultaneously present within the cooling channel 5 . At a nominal temperature, the gas bubbles and the liquid columns preferably occupy a similarly large volume. The gaseous portion of the working medium 6 particularly preferably occupies 30% to 70% of an internal volume of the cooling channel 5 at the nominal temperature, with the remaining internal volume being occupied by the liquid portion of the working medium 6 . Depending on the temperature of the cooling device 1, the volume ratio changes as a result of evaporation or condensation of the working medium 6.

When the base region 2 of the cooling device 1 is heated by the component 101, the cooling channel 5 and the working medium located therein are heated. A combination of evaporation, condensation, convective heat transport and heat conduction transports the heat away from the base area 2 and thus cools the component 101. The working medium 6 particularly preferably has a critical temperature that is greater than a maximum operating temperature. The working medium 6 preferably has a critical temperature of at least 233 K, preferably at least 273 K, particularly preferably at least 373 K, and in particular at most 533 K. A temperature of a substance at the critical point is regarded as the critical temperature. This ensures that the working medium 6 can be present in two phases within the cooling channel 5 in a preferred operating range in which the working medium 6 is present in particular at temperatures from 222 K to 473 K, in particular from 273 K to 373 K. The working medium 6 is preferably an organic refrigerant, which is used for example in vehicle air conditioning systems, such as in particular 2,3,3,3-tetrafluoropropene, also referred to as R1234yf, R1233zd(E), etc. The working medium 6 particularly preferably has a melting point which maximum 273K, preferably at most 233K, more preferably at most 213K.

The cooling channel 5 runs through the cooling device 1 as a channel. The cooling channel 5 has an inner wall 53 . The inner wall 53 is the side of the cooling channel 5 that is in direct contact with the working medium 6 . One or more surface structures 54 with an increased square roughness are formed on the inner wall 53 of the cooling channel 5 in a targeted and locally delimited manner in comparison to the adjacent cooling channel sections, which essentially have the same roughness, in particular due to a manufacturing process that is used in the same way, which is used in the production of the Cooling channel has significantly shaped the surface in these cooling channel sections. The inner wall 53 of the cooling channel 5 is, for example, structured, in particular more heavily roughened, on the specifically locally limited surface structure 54 . The inner wall 53 of the cooling channel 5 is therefore not smooth, for example, on the specifically locally limited surface structure 54 . The inner wall 53 has, for example, a large number of elevations and/or depressions on the specifically locally limited surface structure 54, the elevations and/or depressions forming said surface structure 54. The surface structure 54 is locally limited, that is to say the surface structure 54 is only formed on a limited part and/or along a limited length section of the inner wall 53 of the cooling channel 5 . Correspondingly, other parts of the inner wall 53 of the cooling channel 5 do not have such a specifically locally limited surface structure 54 with increased square roughness, but are smooth. Said locally limited surface structure 54 on the inner wall 53 of the cooling channel 5 is in direct contact with the working medium 6 . In this way, heat can be emitted directly from the specifically locally limited surface structure 54 to the working medium 6 . The inner wall 53 of the cooling channel 5 can have a locally increased roughness on the surface structure 54, for example. The locally limited surface structure 54 on the inner wall 5 of the cooling channel 5 can be produced, for example, by sandblasting, glass bead blasting, etching or milling. The inner wall 5 of the cooling channel 5, which previously had a smooth surface, for example, is treated by sandblasting, etching or milling, and thus the locally limited surface structure 54 in the area in which the inner wall 5 of the cooling channel 5 was treated in this way generated with increased quadratic roughness. The inner wall 53 of the cooling channel 5 is, for example, roughened by the treatment or structured in some other way and thus has a locally limited surface structure of this type. Furthermore, the cooling device 1 or at least parts of the cooling device 1 can be produced by means of a 3D printing process. Thus, the cooling channel 5 in the cooling device 1 can be made partially smooth and partially with said locally limited surface structures 54 .

One or more locally limited surface structures 54 with an increased square roughness can be formed on the inner wall 53 of the cooling channel 5 . The exemplary embodiments illustrated in the figures differ in the locations at which such locally limited surface structures are provided in the cooling channel 5 . The direction g in the figures represents the direction of gravity. The figures each show the preferred orientation of the respective exemplary embodiment of the cooling device 1 with respect to the direction g of gravity.

In the first exemplary embodiment illustrated in FIG. 1, the locally limited surface structures 54 are formed in the base region 2 with an increased squared roughness. The cooling channel 5 has a locally limited surface structure 54 in each of the deflection segments 52 in the base area 2 of the cooling device 1 . These locally limited surface structures 54 are each formed on one side in the deflection segments 52 . The deflection segments 52 in the base area 2 of the cooling device 1 are U-shaped. One side of the U-shaped bend has a locally limited surface structure 54 with an increased square roughness, the other side of the U-shaped bend of the deflection segment 52 having no such locally limited surface structure 54, ie it is smooth, for example. Preferably, as in the exemplary embodiment illustrated in Fig. 1, all deflection segments 52 have said specifically locally limited surface structure 54 formed on one side of deflection segment 52, surface structures 54 preferably being formed on all deflection segments 52 on the same side of deflection segments 52 . The heat of the component 101 is absorbed by the base area 2 and given off to the working medium 6 which is in the part of the cooling channel 5 which is arranged in the base area 2 . Located in the cooling channel 5 to the Bubbles forming the above-mentioned locally limited surface structures 54 now preferably migrate into the straight central segments 51 on the side of the deflection segment 52 which has the locally limited surface structure 54 . This results in a preferred direction of the flow at each deflection segment 52 in the base area 2 . Viewed over the entire cooling device 1, this results in a superimposed circulating movement.

In the second exemplary embodiment of the cooling device 1 illustrated in FIG. 2 , the surface structures 54 that are specifically delimited locally and have an increased squared roughness are arranged in the base region 2 of the cooling device 1 . The deflection segments 52 are formed in the base area 2 in a row next to one another. Said locally limited surface structures 54 are formed in the deflection segments 52 lying on the outside in the row of deflection segments 52 . In this exemplary embodiment, the two outermost deflection segments 52 each have such a locally limited surface structure 54 . The other deflection segments 52 arranged in the base area 2 do not have such a locally limited surface structure 54, but rather have a smooth surface.

In the exemplary embodiment illustrated in FIG. 3 , the surface structures 54 , which are locally limited in a targeted manner, are formed with an increased square roughness in the central segments 51 of the cooling channel 5 . In this way, the cooling device 1 can advantageously also be optimized in non-preferred orientations, as shown in FIG. 3 . The base area 2 can also be arranged above the deflection area 3 of the cooling device 1 with respect to the direction of gravity g. If the cooling device 1 is arranged in this way, the liquid phase of the working medium 6 preferably collects in the deflection area 3 of the cooling device. If heat is now introduced into the base area 2 , this is transported via thermal conduction via the intermediate area 4 in the direction of the deflection area 3 . If the flow of heat reaches said locally limited surface structures 54 in the middle segments 51 of the cooling channel, bubbles form in the cooling channel 5 in the area of the locally limited surface structures 54 in the middle segments 51 of the cooling channel 5 Surface structures 54 the cooling device 1 work despite unfavorable orientation as a pulsating heat pipe.

Of course, further exemplary embodiments and mixed forms of the exemplary embodiments shown are also possible.

Claims

Expectations 1. Cooling device for cooling components (101) comprising: - a base area (2) which can be thermally conductively connected to a component (101) to be cooled, - a deflection area (3), - an intermediate area (4) between the base area (2) and the deflection area (3), and - a cooling channel (5) which is designed in a meandering shape and has a number of central segments (51) and a number of deflection segments (52), - the middle segments (51) each extending from the base area (2) to the deflection area (3), - wherein the deflection segments (52) each form a reversal of direction within the base area (2) and within the deflection area (3) and connect two middle segments (51) to each other, - the cooling channel (5) being filled with a working medium (6) which is present in the cooling channel (5) in gaseous and liquid form at the same time, characterized in that an inner wall (53) of the cooling channel (5) has at least one locally limited surface structure (54 ) with increased roughness, which is in contact with the working medium (6). 2. Cooling device according to claim 1, characterized in that the locally limited surface structure (54) of the inner wall (53) of the cooling channel (5) is formed in at least one deflection segment (52) in the base area (2) of the cooling device (1). 3. Cooling device according to claim 2, characterized in that the locally limited surface structure (54) is formed on one side in the deflection segment (52) in the base area (2). 4. Cooling device according to one of the preceding claims, characterized in that the deflection segments (52) in the base region (2) are formed in a row next to one another, with the locally limited surface structure (54) in at least one deflection segment (52 ) is formed, wherein at least one in the row inner deflection segment (52) has no locally limited surface structure (54). 5. Cooling device according to Claim 4, characterized in that a locally limited surface structure (54) is formed in each of the two outer deflection segments (52) in the base area (2), the deflection segments (52) lying on the inside in the row not having a locally limited surface structure ( 54). 6. Cooling device according to one of the preceding claims, characterized in that at least one locally limited surface structure (54) is formed in at least one central segment (51). 7. Cooling device according to claim 6, characterized in that at least one locally limited surface structure (54) is formed in all central segments (51). 8. Cooling device according to one of the preceding claims, characterized in that the inner wall (53) of the cooling channel (5) in the region of the local surface structure (54) has a locally increased roughness. 9. Cooling device according to one of the preceding claims, characterized in that the inner wall (53) of the cooling channel (5) in the area of the local surface structure (54) has a higher roughness than the inner wall (53) of the cooling channel (5) at the deflection segments ( 52) in the deflection area (3). 10. Electronics assembly comprising: - a component (101), in particular a semiconductor component, and - A cooling device (1) according to any one of the preceding claims, - wherein the component (101) is thermally conductively connected to a base area (2) of the cooling device (1).